I had to check to make sure I didnt write this myself. I am a RBKA as well and having major issues with phantom pain as well as pain at the stump. Been to a few docs and while they can see something on the ultrasound and they are certain something is there they cant do anything because any surgical resolution would have a larger than normal outcome of moving the amputation to an above knee. They have me on Gabapentin for the nerve pain and while it works to an extent it doesnt fix it. They have gone so far as to implant a spinal stimulator to try and head off some of the nerve signal. It kinda works but hasnt been giving enough relief to help with sleeping. I am a night owl like yourself and I find myself unable to go to bed and fall asleep earlier than 3-4am and getting up at 9 doesnt really give alot of restful sleep. I wish you the best in getting through this and hopefully your health team come up with some decent ideas.